corelokt
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- Duffield, VA. (East of nowhere).
I've a 700r4 in my truck. Thought I'd make a run down of it all.
It came from a diesel, so:
TV cable and bracket were there.
Torque converter was right.
Fly wheel was on donor engine. (You need the one for the 700R4). They look the same, they are not, the bolt holes to the torque converter are closer in for the 700R4.
Diesel transmission has no electronics, so no lock-up wires.
Transmission was from a 1988, the crossmember was wrong. It took shimming, combining parts, etc, to make it fit.
Driveshafts & U-joints worked (new T-case was a NP208 also), though the transmission was about 3 inches longer.
Intake came off to fit the TV cable linkage.
Speedometer gear from the T400 was needed to get the speed right.
Here is more info I gathered:
700r4 into cucv
You will need a tv cable bracket, they don't make these any more so will have to find one in a junkyard or make one, there is a pic on this thread. will need a tv cable rod, this hooks onto side of pump/throttle linkage and connects to tv cable at the back of motor. I called local chevy dealer, they can get them through there classic vehicle distributor for $25. Will need a tv cable, I got mine at local parts store for $16. New flex plate, also might want to consider getting a new torque converter, I got the flex plate for $60 and the TC for $100, it is a 1600 stall with lockup. Also will need the lockup kit, I got mine for $100. This is where I got TC, Flexplate, and Lockup kit Bowtie Overdrives . The 700r4 is only 1/2 an inch longer than the turbo 400, I didn't need to move the trans/transfer case crossmember, will also need an NP208 from the back of a turbo 350, make sure it comes with adapter, this is a direct bolt up to the back of the 700r4, NO modifications required! Drive shafts will NOT need to be modified, they will bolt right up to the NP208 that came of the turbo 350. That's it, as far as shifter linkages, and trans cooler lines for trans/transfercase, everything is the same no modifications required. Will need to use dipstick tube from the 700r4 it is a little different than the turbo 400.
6.2 diesel torque converter for a 700R4/4L60 has several differences than those for gas engines. Besides the lower stall speed, it is specially built to holding back when coming down a hill in a low gear. Note that for diesels, they also come in three-lug drive, and six-lug drive (like your TH400 has now).
Standard three lug converters are easy to buy for the same price as gas converters. The six-lug units cost more and also have HD clutch disks and dampers inside. I just had one custom made for my truck for $225. A standard LD three-lug converter is around $125.
The 700R4/4L60 also has several differences for diesel use. I suggest you find a diesel trans with a HD case - and something at least a 1988 vintage, and 1991 is even better. There were many, many problems, fixes, and changes along the way. The best of the series - for use in a 6.2 or 6.5 - is a 1991-1992 4L60 upgraded with better 3-4 clutches and a few 4L65 parts that retrofit. Note that GM simply changed the name of the 700R4 to the "4L60" around 1991.
Do you have to trim the output shaft out of the 700?
I had to grind off about 1 inch, I tried to use the sawzall and a carbide tip blade but that didn't work so I used my angle grinder. Also had to use a 2 inch spacer that I got from A & Reds .
I just custom built my own 4L60 for my 6.2 Blazer mini-motorhome. I was tempted to buy a HD rebuilt trans - but could not find what I wanted. Many of the "super" upgraded units for sale have very aggressive clutch packs and mods for racing purposes. A racing-trans is not what I wanted. I wanted a heavy-built trans that can last a long time against a somewhat low power engine.
My Blazer first has a TH400. I then used a 1986 700R4 against 3.08 ratio axles. Ran well enough, but was underpowered. I then installed a Banks turbo and soon after -the trans blew. I've now got 3.73 axles and the 1991 4L60 I just built - and so far - I love it. Time will tell in regard to longevity. I'd rather have a 4L80, but the need and price of a separate controller is extremely expensive. 4L80E is the "new and improved" version of the old TH400 (which got renamed to the 3L80).
I've got converter lockup controlled by a 4th gear pressure switch along with a manual switch. It is disconnected by the brake switch, AND the TPS (throttle position switch) on the injection pump. If you are converting your truck from the TH400, over to the 700R4/4L60 - I suggest you remove your VRV from the injection pump, and install a TPS switch. This way, when ever you take your foot of the "gas pedal", the converter cannot lock. It's a nice feature.
A NP205 that came off a turbo 350 will work with the 700r4, must do 2 of 3 things first though. First will need a 2 inch spacer, here is two places that have them, Offroad Design - Fullsize Chevy GM 4x4 Suspensions, Parts and Performance and A & Reds . Then one of these 2 things will work, will either need to grind off about 1 inch of tail shaft or tear transmission down and get a shorter tail shaft, I just grind them down unless the trans needs a rebuild. Yes an NP205 with PTO will work with the 700r4. As far as a diesel or gas 700r4, there exactly the same except for the governor and the tv cable spring. I am using a 700r4 out of an s-10 blazer and didn't change the governor or tv cable spring, seems to work pretty good. If shifts feel delayed or not firm, then just change governor and tv cable spring, both or really easy to change, governor is at back of trans, just pry off round cover on the left side of trans pull out governor put new one in. The tv cable spring is under pan, just remove pan, then remove tv cable spring assembly replace with new one and reinstall.
It came from a diesel, so:
TV cable and bracket were there.
Torque converter was right.
Fly wheel was on donor engine. (You need the one for the 700R4). They look the same, they are not, the bolt holes to the torque converter are closer in for the 700R4.
Diesel transmission has no electronics, so no lock-up wires.
Transmission was from a 1988, the crossmember was wrong. It took shimming, combining parts, etc, to make it fit.
Driveshafts & U-joints worked (new T-case was a NP208 also), though the transmission was about 3 inches longer.
Intake came off to fit the TV cable linkage.
Speedometer gear from the T400 was needed to get the speed right.
Here is more info I gathered:
700r4 into cucv
You will need a tv cable bracket, they don't make these any more so will have to find one in a junkyard or make one, there is a pic on this thread. will need a tv cable rod, this hooks onto side of pump/throttle linkage and connects to tv cable at the back of motor. I called local chevy dealer, they can get them through there classic vehicle distributor for $25. Will need a tv cable, I got mine at local parts store for $16. New flex plate, also might want to consider getting a new torque converter, I got the flex plate for $60 and the TC for $100, it is a 1600 stall with lockup. Also will need the lockup kit, I got mine for $100. This is where I got TC, Flexplate, and Lockup kit Bowtie Overdrives . The 700r4 is only 1/2 an inch longer than the turbo 400, I didn't need to move the trans/transfer case crossmember, will also need an NP208 from the back of a turbo 350, make sure it comes with adapter, this is a direct bolt up to the back of the 700r4, NO modifications required! Drive shafts will NOT need to be modified, they will bolt right up to the NP208 that came of the turbo 350. That's it, as far as shifter linkages, and trans cooler lines for trans/transfercase, everything is the same no modifications required. Will need to use dipstick tube from the 700r4 it is a little different than the turbo 400.
6.2 diesel torque converter for a 700R4/4L60 has several differences than those for gas engines. Besides the lower stall speed, it is specially built to holding back when coming down a hill in a low gear. Note that for diesels, they also come in three-lug drive, and six-lug drive (like your TH400 has now).
Standard three lug converters are easy to buy for the same price as gas converters. The six-lug units cost more and also have HD clutch disks and dampers inside. I just had one custom made for my truck for $225. A standard LD three-lug converter is around $125.
The 700R4/4L60 also has several differences for diesel use. I suggest you find a diesel trans with a HD case - and something at least a 1988 vintage, and 1991 is even better. There were many, many problems, fixes, and changes along the way. The best of the series - for use in a 6.2 or 6.5 - is a 1991-1992 4L60 upgraded with better 3-4 clutches and a few 4L65 parts that retrofit. Note that GM simply changed the name of the 700R4 to the "4L60" around 1991.
Do you have to trim the output shaft out of the 700?
I had to grind off about 1 inch, I tried to use the sawzall and a carbide tip blade but that didn't work so I used my angle grinder. Also had to use a 2 inch spacer that I got from A & Reds .
I just custom built my own 4L60 for my 6.2 Blazer mini-motorhome. I was tempted to buy a HD rebuilt trans - but could not find what I wanted. Many of the "super" upgraded units for sale have very aggressive clutch packs and mods for racing purposes. A racing-trans is not what I wanted. I wanted a heavy-built trans that can last a long time against a somewhat low power engine.
My Blazer first has a TH400. I then used a 1986 700R4 against 3.08 ratio axles. Ran well enough, but was underpowered. I then installed a Banks turbo and soon after -the trans blew. I've now got 3.73 axles and the 1991 4L60 I just built - and so far - I love it. Time will tell in regard to longevity. I'd rather have a 4L80, but the need and price of a separate controller is extremely expensive. 4L80E is the "new and improved" version of the old TH400 (which got renamed to the 3L80).
I've got converter lockup controlled by a 4th gear pressure switch along with a manual switch. It is disconnected by the brake switch, AND the TPS (throttle position switch) on the injection pump. If you are converting your truck from the TH400, over to the 700R4/4L60 - I suggest you remove your VRV from the injection pump, and install a TPS switch. This way, when ever you take your foot of the "gas pedal", the converter cannot lock. It's a nice feature.
A NP205 that came off a turbo 350 will work with the 700r4, must do 2 of 3 things first though. First will need a 2 inch spacer, here is two places that have them, Offroad Design - Fullsize Chevy GM 4x4 Suspensions, Parts and Performance and A & Reds . Then one of these 2 things will work, will either need to grind off about 1 inch of tail shaft or tear transmission down and get a shorter tail shaft, I just grind them down unless the trans needs a rebuild. Yes an NP205 with PTO will work with the 700r4. As far as a diesel or gas 700r4, there exactly the same except for the governor and the tv cable spring. I am using a 700r4 out of an s-10 blazer and didn't change the governor or tv cable spring, seems to work pretty good. If shifts feel delayed or not firm, then just change governor and tv cable spring, both or really easy to change, governor is at back of trans, just pry off round cover on the left side of trans pull out governor put new one in. The tv cable spring is under pan, just remove pan, then remove tv cable spring assembly replace with new one and reinstall.
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